同步电复律不适用于（）
A.心房扑动
B.心房颤动
C.心室颤动
D.室上性心动过速
E.室性心动过速
参考答案：C
— It's reported that the new underground line has been completed.
— Yes, but it hasn't been made clear _____ it's to be opened to traffic. [ ]
A. that
B. who
C. what
D. when
大型油罐应设置（）自动灭火系统。
A、泡沫灭火系统
B、二氧化碳灭火系统
C、囱代烷灭火系统
D、喷淋灭火系统
